The Convention on the Future of the European Union, also known as the European Convention, was a body established by the European Council in December 2001 as a result of the Laeken Declaration. Inspired by the Philadelphia Convention that led to the adoption of the United States federal Constitution, its purpose was to produce a draft constitution for the European Union for the Council to finalise and adopt. The Convention finished its work in July 2003 with their Draft Treaty establishing a Constitution for Europe. See History of the European Constitution for developments after this point.

The Treaty establishing a Constitution for Europe was an unratified international treaty intended to create a consolidated constitution for the European Union (EU). It would have replaced the existing European Union treaties with a single text, given legal force to the Charter of Fundamental Rights, and expanded qualified majority voting into policy areas which had previously been decided by unanimity among member states.